Marx and The Communist Manifesto

It has been said that Marx admired capitalism. At the same time, Marx delivered a demolishing blow to the basis of this mode of production.  Pick up some quotes from the Communist Manifesto (or other works by Marx) that show his admiration and condemnation of capitalism. How is it possible for him to both admire and condemn the capitalist system simultaneously? What is it about capitalism that he admires, and what is it that he condemns? And what is the relationship between the two?